It wasn't a pretty possession, but Arkansas will take it.

Senior guard Manuale Watkins hit an awkward, off-balance jumper as the shot clock expired with 31 seconds to play, helping the Razorbacks upend No. 21 South Carolina 83-76 on Wednesday at Colonial Life Arena in Columbia, S.C.

Jaylen Barford finished with 23 points, and Dusty Hannahs added 20 points, including four 3-pointers, for the Razorbacks, who erased an early double-digit deficit and answered every challenge from the Gamecocks in the second half.

Sindarius Thornwell scored a game-high 27 points for South Carolina, and Chris Silva tied his career-high with 16 points before fouling out in the second half for the Gamecocks (20-6, 10-3 Southeastern Conference).

Arkansas was clinging to a 77-76 lead with less than a minute to play when Watkins wound up with the ball as the shot clock was running out. He got to the foul line extended and pushed up a shot that hit the backboard and the back rim before falling through the net.

"Sometimes you create your luck," Arkansas coach Mike Anderson said of Watkins' shot. "He didn't call bank, but it's good."

The Gamecocks turned it over on their next possession, and the Razorbacks hit enough free throws down the stretch to seal the win.

Arkansas (19-7, 8-5 SEC) is squarely on the NCAA Tournament bubble according to multiple bracket projections. The Razorbacks needed a quality win over a ranked opponent and got one, thanks in part to Hannahs, who hurt the Gamecocks from both the outside and the inside. He scored nine consecutive points for Arkansas during one stretch in the second half to help fend off a South Carolina run.

"South Carolina is a heck of a basketball team, but some things smiled on us today," Anderson said. "This is a great win on the road against a Top 25 team, but this is just the beginning for us."

The Gamecocks are still in good position for an automatic bid to the NCAA Tournament. However, South Carolina has dropped its past two home games, conjuring up memories of last year's late collapse that kept the Gamecocks out of the field.

"That was disappointing, but I'm not surprised," said South Carolina coach Frank Martin, who told reporters that he walked out of Monday's practice due to a lack of energy from his squad. "Our team mindset hasn't been where it needs to be."

Arkansas extended its lead to double digits early in the second half before South Carolina found a spark on the defensive end. Thornwell blocked a shot, leading to a breakaway dunk, and Silva threw down a dunk off an alley-oop that cut Arkansas' lead to 55-54 with 10:55 to play.

Hannahs answered with a 3-pointer and got to the rim twice to help squash the South Carolina surge.

Arkansas senior forward Moses Kingsley finished with 16 points and seven rebounds, and junior guard Daryl Macon provided a boost off the bench with 13 points. The Razorbacks' bench outscored the Gamecocks' reserves 18-8.

South Carolina used a 14-0 run early in the first half to take a 19-5 lead. Arkansas answered right back, running off 15 consecutive points and taking a 20-19 lead on a 3-point by Macon with 9:22 left in the first half.

Barford had 17 in the first half, and the Razorbacks led 39-32 at the intermission.

Thornwell and Martin each pointed to the team's defense as the primary issue in the loss.

"We're not guarding," Thornwell said. "We haven't been playing the way we're supposed to, and it shows."

Martin added, "We're not doing anything right defensively right now."

NOTES: For the third time in his career, South Carolina G Sindarius Thornwell was named SEC Player of the Week. He averaged 36 points, 12.5 rebounds and three assists last week against Alabama and Mississippi State. ... Arkansas coach Mike Anderson inserted sharp-shooting G Dusty Hannahs into the starting lineup. ... The Razorbacks hit 7 of 14 3-point attempts. South Carolina entered the game leading the nation in 3-point-percentage defense. ... South Carolina travels to Vanderbilt and Arkansas returns home to face Ole Miss on Saturday.